R_000030_BUS_CNTL
tmp = RREG32(R_000030_BUS_CNTL);
WREG32(R_000030_BUS_CNTL, (tmp & 0xFFFFFFFF) | 0x00000044);
WREG32(R_000030_BUS_CNTL, (tmp & 0xFFFFFFFF) | 0x00000042);
WREG32(R_000030_BUS_CNTL, (tmp & 0xFFFFFFFF) | 0x00000040);